Trolley wheel

ABSTRACT

A trolley for pipe rail conveyor systems provided with a plurality of rail-engaging wheels, each wheel comprising two companion wheel sections which are mounted for independent rotation which occurs when the trolley traverses a curved portion of the pipe rail, said wheel sections when so mounted forming between them a circumferential groove to receive the pipe rail on which the wheel is to ride, the inner end of said wheel sections being spaced from each other, the groove having a contour formed by arcs having a common center and a radius equal to the radial distance from said common center to the circumference of the pipe rail, the contour of the groove including straight outer portions which are continuations of said arcs and tangent to said arcs, said tangent portions serving to resist lateral bodily movement of the wheel sections or swinging movement of the trolley on the wheel about the axis of the pipe rail.

United States Patent [1 1 Harvey [451 Sept. 18,1973

Primary Examiner-Gerald M. Forlenza Assistant Examiner-D. W. Keen Attorney-Arthur A. Johnson [57] ABSTRACT A trolley for pipe rail conveyor systems provided with a plurality of rail-engaging wheels, each wheel comprising two companion wheel sections which are mounted for independent rotation which occurs when the trolley traverses a curvedportion of the pipe rail, said wheel sections when so mounted forming between them a circumferential groove to receive the pipe rail on which the wheel is to ride, the inner end of said wheel sections being spaced from each other, the groove having a contour formed by ares having a common center and a radius equal to the radial distance from said common center to the circumference of the pipe rail, the contour of the groove including straight outer portions which are continuations of said arcs and tangent to said arcs, said tangent portions serving to resist lateral bodily movement of the wheel sections or swinging movement of the trolley on the wheel about the axis of the pipe rail.

1 Claim, 4 Drawing Figures I F r/ 1 F /7 TROLLEY WHEEL This invention relates to trolleys for use in pipe rail conveyor systems, and more particularly to an improved wheel and wheel mounting for such trolleys.

Such conveyor systems comprise a suitable overhead pipe rail of such length as is required and having straight and curved sections and sometimes ascending and descending sections to meet the particular needs of the user. Such conveyor systems are used in many different kinds of businesses, such as by clothing manufacturers, dry cleaners, and others requiring transportation of goods from place to place along a definite path.

At the present time, trolleys used with such systems each comprises a frame in which is mounted-two'parallel wheels, each wheel having a bearing on which it rotates.

Two such trolleys may be connected together in spaced relation to move as aunit along the pipe rail, and means are provided between the two trolleys for supporting hangers or other means containing goods to be transported.

The wheels of the trolleys each has a circumferential groove having a surface, substantially semicircular in profile, to receive and ride on the upper surface of the pipe rail. l-leretofore the radius of the groove was larger than the radius of the circumference of the pipe, apparently for the purposeof obtaining virtually point-topoint contact between the surface of the wheel and that of the pipe rail. v

Trolleys so constructed were unsatisfactory because in riding around a curved section of the pipe rail the outer edge of the wheel I on the inside of the curve would slip on the pipe rail because the wheel would be driven by the outer side of the pipe rail which is longer than the inner side and therefore drivesv the wheel faster. As a result a severe rubbing or grinding action was produced by the side edgeof the wheel against the inner surfaceof the curved pipe rail, such rubbing wear having at times actually cutting through the pipe rail and requiring sections of the pipe rail to be replaced at considerable cost and inconvenience.

The wearing action of the. wheel as heretofore made on the pipe rail was increased when the trolley as usual has two spaced wheels because when the trolley is traversing over a curved section of the pipe rail, the axis of neither wheel can be parallel with the radius of the curve, thereby causing the leading portion of the outside edge of the wheels tovabrade and wear the pipe rail.

These difficulties have been obviated by the present invention by making each of the wheels in two sections which preferably are alike, each section being mounted on its own antifriction bearing and rotatable independently 'of the other section,v thereby permitting the tread surfaces of the wheel sections respectively engaging the inside and outside surfaces of the-pipe railto rotate at different speeds. By having thewheel formed of two wheel sections, the concave tread surfaces of the wheel sections may be on a radius equal to the radius of the pipe rail and on the same center, thereby. better supporting the trolley against lateralmovement around the axis of the pipe rail.

With the split-wheel arrangement of the present invention it is possibleto reduce substantially the radius of a 90 bend in the pipe rail.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

FIG. 1 shows a pipe rail as used with overhead conveyor systems showing two trolleys connected together.

FIG. 2 shows the positions of two connected trolleys riding on a curved section of a pipe rail.

FIG. 3 is a transverse section of a trolley according to the present invention, taken on line 3-3 of FIG. 1.

FIG. 4 is a horizontal section taken on the line 4--4 of FIG. 1, showing the arrangement of the wheels of the present invention.

As shown in the accompanying drawings, the trolley of the present invention comprises a frame 10 which is rectangular and of inverted U-shaped in cross section. The frame 10 has a top 11, sides l2.and ends 13. As shown in FIGS. 1 and 2, two trolleys are connected together by a rod 14 having a swivel connection 15 with the top 11' of the trolleys to maintain the trolleys in spaced relation on the pipe rail 16. Extending transversely across the frame 10 are two spaced wheel supporting bolts 17.

Heretofore, each trolley wheel consisted of a single piece 'of metal having a circumferential arcuate groove to form treadportions to receive the round top surface of the pipe rail 16. The radius of the groove was slightly greater than that of the outside surface of the pipe rail so; that point-to-point contact could be had between the wheel and the pipe rail. This was satisfactory when the trolley was riding on a straight section of the pipe rail. However, it was not satisfactory when it was necessary for the trolley to traverse a curved section of the pipe rail because, when driven by the outside surface 16a of the pipe rail, theinner part of the wheel would have a greater peripheral speedthan the linear distance traveled on the pipe rail, and therefore the outer surface of the inner wheel would 'abrade and finally sever the inner surface 16b of the pipe rail which it engages.

. This damage has been obviated by the present invention by making each trolley wheel in two vertically divided independently supported wheel sections so that when rounding a curve, the inside wheel section can rotate at a slower speed than the outer wheel section and not rub or abrade the inside surface 16b of the pipe rail.

Accordingly, as shown in the drawings, particularly FIG. 3, the wheels of the present invention each has two wheel sections 18 each rotatably mounted on a ball bearing unit 19 carried by the bolt 17. The ball bearing units 19 are of such length that whenassembled on the bolt 17 they fill the space between the sides 12 of the frame and abut each other at the middle of the bolt 17. The bases of the bearing units 19 are held stationary when a nut 20 on each'of the bolts is tightened. The

bearing units 19 hold the wheel" sections 18 against moving laterally so that theyremain spaced from each other and spaced from the sides 12 of the frame.

Each wheel section 18 has a concave arcuate tread surface 22 which faces a like surface 22 on the opposite wheel section. The arcuate surfaces 22 on the wheel sections have a common. center and a radiuswhich is equal to the radius of the outside surface of the pipe rail so that a substantial portion of the pipe rail is engaged by the tread portions of the wheel sections. The outer end of each arcuate surface is extended by straight portions 23 which are tangent to the arcuate surface. These straight portions 23 are provided to prevent the wheel sections from riding up on the upper surfaces of the pipe rail in the event a severe lateral thrust is applied to the trolley. The extreme outside edges 23 of the wheel sections 18 may be slightly rounded off as shown to avoid abrading the pipe rail in the event that the lateral thrust on the trolley is excessive.

The trolleys may have any suitable supporting means such, for instance, as shown in FIG. 1 where there are depending hook-like members 25 extending through apertures 26 in the sides 12 of the frame. The lower ends of the hook members 25 may be connected by a rod 27 having eyes 28 receiving the upturned ends 29 of the hook members.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. In a trolley for overhead conveyor systems comprising an elongate rectangular frame which is inverted U-shape in cross section, said frame having parallel sides; two spaced parallel rods supported in said sides and extending transversely of said frame: the improvement comprising two independently rotatable antifriction hearings on each said rod; and a wheel having two independently rotatable wheel sections, one mounted on'each of said bearings and in laterally spaced relation, said wheel sections each having a concave surface to conform to and engage the upper surface of a pipe rail substantially circular in cross section with which the trolley is to be used, each concave surface being arcuate and having a radius on the center of and equal to the radius of the outside surface of the pipe rail, the adjacent edges of the wheel sections being spaced from each other and the length of each arcuate surface being approximately 45, and being continued toward the outer end of the wheel section on a line tangent to said arcuate surface. 

1. In a trolley for overhead conveyor systems comprising an elongate rectangular frame which is inverted U-shape in cross section, said frame having parallel sides; two spaced parallel rods supported in said sides and extending transversely of said frame: the improvement comprising two independently rotatable antifriction bearings on each said rod; and a wheel having two independently rotatable wheel sections, one mounted on each of said bearings and in laterally spaced relation, said wheel sections each having a concave surface to conform to and engage the upper surface of a pipe rail substantially circular in cross section with which the trolley is to be used, each concave surface being arcuate and having a radius on the center of and equal to the radius of the outside surface of the pipe rail, the adjacent edges of the wheel sections being spaced from each other and the length of each arcuate surface being approximately 45*, and being continued toward the outer end of the wheel section on a line tangent to said arcuate surface. 